1 Field of the Invention
This invention relates to compositions including sterols and their esters, particularly, cholesteryl esters, a 2,6-dihalogenated-phenol and one or more pesticides. These compositions have utility in the management of ticks. The compositions are used to attract, trap and/or kill these pests.
2 Description of the Prior Art
Ticks transmit a greater variety of infectious diseases than any other group of hematophagous anthropods. Ticks along cause a $270 million loss per year to the U.S. cattle industry. For this reason there is interest in controlling and/or eradicating these pests.
As with insects, tick mating is regulated primarily by sex pheromones. Phenolic compounds such as 2,6-dichlorophenol (2,6-DCP) have been found in at least 14 species of ixodid ticks. These pheromones are secreted by sexually mature females in order to attract males [Sonenshine, D. E., Annu. Rev. Entomol., Vol. 30, (1985), pp. 1-28].
Female tick decoys have been made which incorporate 2,6-DCP and a toxicant into a device to lure and kill male ticks "U.S. Pat. No. 4,884,361, issued Dec. 5, 1988].
There is a major disadvantage inherent when using these prior art compositions in controlling ticks. While male ticks recognize phenolic compounds such as 2,6-dichlorophenol and 2,6-dibromophenol, (2,6-DBP) [Sonenshine, et al., J. Chem. Ecol., Vol. 2, No. 2, (1976), pp. 201-209] this recognition does not guarantee mating [Hamilton, et al., J. Chem. Ecol., Vol. 14, No. 1, (1988), pp. 401-410; Sonenshine, et al., Exp. Parasite. Vol. 54, (1982), pp. 317-330]. Male ticks attracted to 2,6-DCP applied to inanimate objects leave the objects without mating thus failing to recognize a potential mate.
It has been found that male ticks (Dermacentor variabilis and Dermacentor andersoni) exhibit probing and mounting behavior when exposed to hexane extracts of female tick cuticle [Hamilton, et al., J. Chem. Ecol., Vol. 14, No. 1, (1988). pp. 401-410]. Apparently, the cuticular lipids act as a mounting sex pheromone (MSP) to initiating mounting and copulation by the male.
It can be seen that there is a need for compositions and methods for their use that will lure male ticks and subsequently keep them in a vicinity for a sufficient time to kill them or alteratively, interrupt their mating cycle.